But there was a rub: Despite moving tickets, SHM wasn't selling music at anywhere near a comparable pace. The three-man DJ/producer crew has sold a mere 99,000 copies of its first long-form release, 2010 compilation Until One, according to Nielsen SoundScan. The act's biggest single, "Save the World," has sold 463,000. Small numbers when compared with other acts capable of selling out arenas, and sales numbers also dwarfed by some of SHM's EDM peers, highlighting a paradox in this year's dance landscape: Pop-leaning EDM often struggles at retail, while less palatable sounds sell more briskly.

EDM's enduring image in 2012 will be that obligatory helicopter shot of 100,000 kids packed in front of a main stage, at festivals like Ultra Music Festival and Electric Daisy Carnival. The communal EDM live experience is such a juggernaut that Robert F.X. Sillerman revived his SFX Entertainment in June just to buy up and consolidate large chunks of it. But when those kids go home, their fan-dom takes on different shapes, depending on which acts they like best.

Some say it's a generational thing: EDM is a youth movement, and people of a certain age just don't buy music. "If you were born after 1979, you could care less about owning a record," says Kathryn Frazer, founder of PR firm Biz3, which represents EDM artists like Skrillex and Bassnectar. Frazier is also a partner in Skrillex's OWSLA label. "It's not in your genetic makeup to either possess one or feel like you have to buy one. There's a whole population that simply does not know that that's a part of the program."

But Skrillex himself challenges that argument: The bass music champion and early mentor Deadmau5 fare well on the sales side. Both have singles that have sold more than 1 million copies each ("Scary Monsters and Nice Sprites" and "Ghosts N Stuff," respectively). Skrillex's two EPs, Bangarang and Grammy Award winner Scary Monsters and Nice Sprites, have sold nearly 1 million copies combined. For primarily instrumental music without a lick of radio support, the numbers are strong.

"Young people won't buy music they're not passionate about," says David Waxman, GM of Ultra Music, home to Deadmau5 and Calvin Harris. "They have to be passionate to spend the money, otherwise they'll just stream."

That's not to say that singles like SHM's "Don't You Worry Child," Interscope artist Zedd's "Spectrum" (394,000 sold) or Big Beat/Atlantic signing Porter Robinson's "Language" (41,000) -- all with sweeping, hopeful melodies -- don't prompt smartphone-hoisting and fervent singalongs at a club or festival. But next to Skrillex's seminal synth-noise onslaught, they don't demand to be owned.

"If there is no radio, it's got to have what I call 'the WTF factor,'" Waxman says. "The second you hear it, you've got to be like, 'What the fuck is this?' If it doesn't have that, it's not going to stand out. It's just going to be wallpaper."

Even in a changing digital world, and a genre that prides itself on bottom-up development, the X factor ends up being rather traditional: radio. Because this final frontier has yet to be conquered, many in the business believe that the best days for EDM sales are still ahead.

"We don't feel that we're stuck, that this is it," says Lawrence Lui, senior director of marketing at Astralwerks, home to SHM, Eric Prydz and radio don David Guetta. "Good old terrestrial radio can take an artist from successful to superstar. As EDM permeates the culture at large, as more and more kids get into it, numbers will increase. Record sales, single sales, all the indicators are saying that it's coming."

Waxman points to Harris' "Feel So Close": The self-sung track is still his biggest hit, despite smash collaborations with Rihanna and Ne-Yo. "It wasn't a top 40 record, but the second radio grabbed it, it catapulted it to the next level," Waxman says.

Or take "Don't You Worry Child," SHM's latest single. The track was recently added to KIIS-FM Los Angeles, WHTZ New York and 130 other top 40 stations. It's sold 350,000 singles (according to SoundScan) and is No. 14 on the Billboard Hot 100. The single's success, Lui says, is buoying Until Now, SHM's new compilation released in late October, which is on pace to best Until One. "People discover them on the radio, buy the single, see there's an album, check out a couple of tracks on the album and buy the album," Lui says. "At least that's what we hope for."

With Clear Channel's recent announcement of Evolution, a new EDM station on its iHeartRadio digital platform -- adding to SiriusXM's BPM and Electric Area -- the environments for such discovery are multiplying, though plans for a major-market, EDM-targeted terrestrial station remain scant.

Waxman says that even Deadmau5 -- with his iconic mouse head, multiple endorsement deals (Nokia, Sonos) and sold-out international tours -- could benefit from a radio hit. "Not because he's trying, not because he wants to create one, but if by chance he has that single that connects," Waxman says, "it will take him to an entirely new level."

Even without radio, Lui is bullish about the business picture for EDM, and not just because Astralwerks has 360 deals with SHM and Prydz, giving the label a cut of their robust touring receipts.

"This is the best generation to be a music fan," he says. "There are so many avenues for people to consume music, and on the flip, there are so many new ways to monetize that. We have to get beyond just looking directly at SoundScan sales. Whether it's the unbelievably immense YouTube and Vevo views that David Guetta and the Swedes get, or Spotify and other streaming services, they all feed into a monetization pie."